View source for GUI Tutorial

{{TOC|side}}

This page will teach you how to create your very own User Interface for Arma.<br>
The second part of this page will dive deeper into the possibilities for creating User Interfaces for Arma 3.


= The Basics =

=== Terminology ===

Before we begin, let us define a few words:
{| class="wikitable" 
|-
! Term
! Meaning
|-
| UI
| '''U'''ser '''I'''nterface. This is a general term that describes anything on a screen that can interface with the user.
|-
| GUI
| '''G'''raphical '''U'''ser '''I'''nterface. a more specific version of UI. It refers to a user interface that has a graphical appearance. 
|-
| Dialog/Display
| Both of them refer to a Graphical User Interface, but within the context of Arma, there are small differences between the two, which is explained [[#createDialog_vs_createDisplay_vs_cutRsc|later in this page]].
|-
| HUD
| '''H'''eads-'''u'''p-'''D'''isplay. A type of display meant for showing information without affecting the ability of the user to move and look around.
|-
| UIEH
| '''U'''ser '''I'''nterface '''E'''vent '''H'''andler. Specific events can happen inside User Interface, for example: when the mouse cursor enters a specific area of the User Interface. If a Handler for that particular event has been created, it will execute any code which has been assigned to that handler. More details about this [[#User_Interface_Event_Handlers|can be found later in this page]].
|}


== Config ==

You will need files for the following parts:
* A config
* Basic control classes
* A display config

Your folder structure could look something like this:
<code style="display: block">mission.World/
├── mission.sqm
├── description.ext
├── UI/
│   ├── BaseControls.hpp
│   ├── RscDisplayName.hpp
</code>

If you are making a mod the description.ext will be called config.cpp and there is no mission.sqm. For an introduction to creating mods, see [[Arma_3:_Creating_an_Addon|Creating An Addon]]. We will call the description.ext and config.cpp the main config to cover both.

=== Main Config Content ===

All display classes are defined in here. Since the config can get very long we will instead include the files in one another with the {{hl|#include}} [[PreProcessor_Commands#.23include|preprocessor]]:
<syntaxhighlight lang="cpp">#include "UI\BaseControls.hpp"
#include "UI\RscDisplayName.hpp"</syntaxhighlight>

=== Parent Controls ===

Also known as base controls. They are the controls that we will be inheriting from. This means that we will copy the content of the parent class without having to rewrite every class. Each parent class has its own unique functionality or appearance determined by their attributes, for example the color of the background is determined by the {{hl|colorBackground}} attribute. If we inherit from this parent class then our dialog control will have the same background color as the parent class. The concept of class inheritance is explained [[Class_Inheritance|here]]. There are three ways to declare these base classes.

==== Import Classes Via import Keyword (Mission Only) ====
{{GVI|arma3|2.02}} You can use the base classes from the game config by using the [[import (Config)|import]] keyword:
<syntaxhighlight lang="cpp">
import RscObject;
import RscText;
import RscFrame;
import RscLine;
import RscProgress;
import RscPicture;
import RscPictureKeepAspect;
import RscVideo;
import RscHTML;
import RscButton;
import RscShortcutButton;
import RscEdit;
import RscCombo;
import RscListBox;
import RscListNBox;
import RscXListBox;
import RscTree;
import RscSlider;
import RscXSliderH;
import RscActiveText;
import RscActivePicture;
import RscActivePictureKeepAspect;
import RscStructuredText;
import RscToolbox;
import RscControlsGroup;
import RscControlsGroupNoScrollbars;
import RscControlsGroupNoHScrollbars;
import RscControlsGroupNoVScrollbars;
import RscButtonTextOnly;
import RscButtonMenu;
import RscButtonMenuOK;
import RscButtonMenuCancel;
import RscButtonMenuSteam;
import RscMapControl;
import RscMapControlEmpty;
import RscCheckBox;
</syntaxhighlight>

==== Declare Classes (Addon Only) ====
We have access to the classes from the game's config when we declare them beforehand.
<syntaxhighlight lang="cpp">
class RscObject;
class RscText;
class RscFrame;
class RscLine;
class RscProgress;
class RscPicture;
class RscPictureKeepAspect;
class RscVideo;
class RscHTML;
class RscButton;
class RscShortcutButton;
class RscEdit;
class RscCombo;
class RscListBox;
class RscListNBox;
class RscXListBox;
class RscTree;
class RscSlider;
class RscXSliderH;
class RscActiveText;
class RscActivePicture;
class RscActivePictureKeepAspect;
class RscStructuredText;
class RscToolbox;
class RscControlsGroup;
class RscControlsGroupNoScrollbars;
class RscControlsGroupNoHScrollbars;
class RscControlsGroupNoVScrollbars;
class RscButtonTextOnly;
class RscButtonMenu;
class RscButtonMenuOK;
class RscButtonMenuCancel;
class RscButtonMenuSteam;
class RscMapControl;
class RscMapControlEmpty;
class RscCheckBox;</syntaxhighlight>

==== Export Classes Via BIS_fnc_exportGUIBaseClasses ====
{{Feature|obsolete}}
Run this command from the debug console:
<sqf>["Default"] call BIS_fnc_exportGUIBaseClasses;</sqf>
The result is copied to the clipboard. Paste it into BaseControls.hpp.

=== Display Config ===

A display class looks like this:
<syntaxhighlight lang="cpp">class RscDisplayName
{
	idd = 1234;
	class ControlsBackground
	{
	};
	class Controls
	{
	};
};
</syntaxhighlight>

{{hl|RscDisplayName}} is the name of the display which will be used in the [[createDisplay]]/[[createDialog]] commands.<br>
{{hl|idd}} is the identification number for the display. It is used in the [[findDisplay]] command. It is mandatory to have it defined. If you don't intend to use the idd you can set it to -1.<br>
{{hl|ControlsBackground}} contains all controls that should stay in the background, for example the dark background of the display.<br>
{{hl|Controls}} contains all important controls, for example buttons.

==== Controls Config ====
The most common way to create a UI in Arma 3 is via the [[Arma 3: User Interface Editor]]. The BIKI page contains a tutorial on it too. You might also be interested in some of the external UI editors listed {{Link|link= https://forums.bohemia.net/forums/topic/226269-tools-utilities-compilation-list-for-arma3/|text= here}}.

A possible output from the GUI Editor might look like this:
<syntaxhighlight lang="cpp">class RscButton_1600: RscButton
{
	idc = 1600;
	x = GUI_GRID_CENTER_X + 0 * GUI_GRID_CENTER_W;
	y = GUI_GRID_CENTER_Y + 0 * GUI_GRID_CENTER_H;
	w = 40 * GUI_GRID_CENTER_W;
	h = 25 * GUI_GRID_CENTER_H;
};
</syntaxhighlight>

The {{hl|idc}} is the identification number for a control. It is used in the [[displayCtrl]] command and can be returned by the [[ctrlIDC]] command.<br>
{{hl|x}} and {{hl|y}} determine the position of the control. {{hl|w}} and {{hl|h}} determine the size. These numbers are given in [[Arma 3: GUI Coordinates|screen coordinates]]. They are somewhat complicated so read about them on the linked page. In the example the {{hl|GUI_GRID_CENTER_X/Y/W/H}} macro is used to keep the UI in the middle of the screen on all possible screen resolutions and UI sizes.<br>
Apart from the editable attributes in the GUI Editor there are even more. Which exactly depends on the {{hl|type}} of the control. Here is an overview over all available control types (CTs).
{{Navbox/CT}}

=== HUDs ===

A Head-Up-Display is just another type of display in Arma 3. All of the above applies to them too. The differences are:
* The player will be able to move and look around while the display is open but can not interact with it.
* The display class has to be listed as part of the RscTitles class:
<syntaxhighlight lang="cpp">
#include "UI\BaseControls.hpp"
class RscTitles
{
	#include "UI\RscMyHUD.hpp"
};
</syntaxhighlight>
* The display class needs the {{hl|duration}} attribute. It determines how long the display will stay on screen. You can choose a large number to make it stay "forever", for example 10^6 (scientific notation: 1e+6) seconds.
<syntaxhighlight lang="cpp">
class RscMyHUD
{
	idd = -1;
	duration = 1e+6;
	{ // ...
</syntaxhighlight>
* The commands for controlling the display are also different:
** HUDs are created with [[cutRsc]].
** [[findDisplay]] does not work on RscTitles displays. Save the display as a variable to [[uiNamespace]] instead. You can get the display with the following code:
<sqf>uiNamespace getVariable ["RscMyHUD", displayNull];</sqf>
<br>
<syntaxhighlight lang="cpp">
class RscMyHUD
{
	idd = -1;
	onLoad = "uiNamespace setVariable ['RscMyHUD', _this select 0];";
	duration = 1e+6;
	class Controls
	{ // ...
</syntaxhighlight>


== Scripting ==

To bring your dialog to life you will need to know how to influence it with sqf commands. A list of all available UI related commands can be found [[:Category:Command_Group:_GUI_Control|here]]. A list of GUI related functions can be found [[:Category:Function_Group:_GUI|here]]. Some control types have special commands such as [[lbAdd]] to add an item to a listbox. A list of commands that are related to the control type can be found on the control type's BIKI page.

=== createDialog vs createDisplay vs cutRsc ===

[[createDialog]], [[createDisplay]] and [[cutRsc]] (for [[#HUDs|HUDs]]) all have their own unique use cases. Here is an overview of what each command does or does not do:
{| class="wikitable" 
|-
! 
! createDialog
! createDisplay
! cutRsc
|-
| Interactable
| {{Icon|checked}}
| {{Icon|checked}}
| {{Icon|unchecked}}
|-
| Player can move
| {{Icon|unchecked}}
| Depends on the parent display
| {{Icon|checked}}
|-
| Player can look around
| {{Icon|unchecked}}
| {{Icon|unchecked}}
| {{Icon|checked}}
|-
| {{Controls|Esc}} closes display
| {{Icon|checked}}
| {{Icon|checked}}
| {{Icon|unchecked}}
|-
| Can be returned by [[findDisplay]]
| {{Icon|checked}}
| {{Icon|checked}}
| {{Icon|unchecked}}
|-
| Returns created display
| Depends on command syntax
| {{Icon|checked}}
| {{Icon|unchecked}}
|-
| Can be created on top of another display
| {{Icon|checked}} (not recommended)
| {{Icon|checked}} (preferred method)
| {{Icon|checked}} (can coexist with other displays but remains uninteractable)
|}

=== User Interface Event Handlers ===
User interface event handlers (UIEH) are a way to detect changes to the UI. A list of them can be found [[User_Interface_Event_Handlers|here]]. Once again, different control types have different UIEHs. For example onButtonClick will detect when a button is clicked. The arguments that are passed to the script also depend on the UIEH. The onButtonClick event will pass the button itself as the only argument in the _this variable. On the other hand onLBSelChanged will pass the control and the selected index as arguments into the script. Since the UIEH is a different script instance, all previously defined local variables will not be available in the code. There are two ways to add an UIEH to a control:

==== Adding UIEHs via config ====
The UIEH is given as an attribute of the control's class like this:
<syntaxhighlight lang="cpp">class ClickMe: RscButton
{
	idc = -1;
	text = "Click Me!";
	onButtonClick = "hint 'You clicked the button!';"; // Display a hint when clicked upon
	x = GUI_GRID_CENTER_X + 10 * GUI_GRID_CENTER_W;
	y = GUI_GRID_CENTER_Y + 12 * GUI_GRID_CENTER_H;
	w = 20 * GUI_GRID_CENTER_W;
	h = 1 * GUI_GRID_CENTER_H;
};
</syntaxhighlight>
The UIEH's name always starts with "on". The code that should be executed is given as a string.

==== Adding UIEHs via script ====
To add UIEHs you can also use [[ctrlAddEventHandler]]. In this case the UIEH does NOT start with "on"!
<sqf>
// This script does the same as the config example
_display = findDisplay 1234;
_ctrl = _display displayCtrl 1000;
_ctrl ctrlAddEventHandler ["ButtonClick", { // Notice the missing "on"!
	params ["_ctrl"];
	hint "You clicked the button!";
}];
</sqf>

=== UI Variables and Serialization ===

Variables containing [[Display|Displays]] or [[Control|Controls]] are not serializable, meaning they can not be stored in save files such as those used by [[saveGame]] and [[loadGame]].
While treating UI variables like other variables does not crash the game when saving, it is at least bad practice and leads to error log entries (see [[Crash Files]]).<br>
UI variables should therefore be used properly like so:

Use the [[uiNamespace]] to store UI variables outside of scripts and functions.
<sqf>
// Wrong, stores MissionDisplay in the missionNamespace:
MissionDisplay = findDisplay 46;
</sqf>
<sqf>
// Correct:
with uiNamespace do {
	MissionDisplay = findDisplay 46;
};
</sqf>
<sqf>
// Also correct:
uiNamespace setVariable ["MissionDisplay", findDisplay 46];
</sqf>

Use [[disableSerialization]] before introducing UI variables in scripts and functions.
<sqf>
// Wrong:
params [["_myCtrl", controlNull, [controlNull]], ["_text", "", [""]]];
_myCtrl ctrlSetText _text;
</sqf>
<sqf>
// Correct:
disableSerialization;
params [["_myCtrl", controlNull, [controlNull]], ["_text", "", [""]]];
_myCtrl ctrlSetText _text;
</sqf>

== Final Result ==

=== description.ext or config.cpp ===

<syntaxhighlight lang="cpp">
#include "\a3\ui_f\hpp\defineCommonGrids.inc"
#include "UI\BaseControls.hpp"
#include "UI\RscDisplayName.hpp"
class RscTitles
{
	#include "UI\RscMyHUD.hpp"
};
</syntaxhighlight>

=== BaseControls.hpp ===

It is only necessary to import/declare the base classes that you actually intend to use.
More usable base controls can be found in the base config of the game. Use the ingame [[Arma_3:_Debug_Console#Buttons|Config Viewer]] to find them.

==== Mission ====
<syntaxhighlight lang="cpp">
import RscObject;
import RscText;
import RscFrame;
import RscLine;
import RscProgress;
import RscPicture;
import RscPictureKeepAspect;
import RscVideo;
import RscHTML;
import RscButton;
import RscShortcutButton;
import RscEdit;
import RscCombo;
import RscListBox;
import RscListNBox;
import RscXListBox;
import RscTree;
import RscSlider;
import RscXSliderH;
import RscActiveText;
import RscActivePicture;
import RscActivePictureKeepAspect;
import RscStructuredText;
import RscToolbox;
import RscControlsGroup;
import RscControlsGroupNoScrollbars;
import RscControlsGroupNoHScrollbars;
import RscControlsGroupNoVScrollbars;
import RscButtonTextOnly;
import RscButtonMenu;
import RscButtonMenuOK;
import RscButtonMenuCancel;
import RscButtonMenuSteam;
import RscMapControl;
import RscMapControlEmpty;
import RscCheckBox;
</syntaxhighlight>

==== Addon ====
<syntaxhighlight lang="cpp">
class RscObject;
class RscText;
class RscFrame;
class RscLine;
class RscProgress;
class RscPicture;
class RscPictureKeepAspect;
class RscVideo;
class RscHTML;
class RscButton;
class RscShortcutButton;
class RscEdit;
class RscCombo;
class RscListBox;
class RscListNBox;
class RscXListBox;
class RscTree;
class RscSlider;
class RscXSliderH;
class RscActiveText;
class RscActivePicture;
class RscActivePictureKeepAspect;
class RscStructuredText;
class RscToolbox;
class RscControlsGroup;
class RscControlsGroupNoScrollbars;
class RscControlsGroupNoHScrollbars;
class RscControlsGroupNoVScrollbars;
class RscButtonTextOnly;
class RscButtonMenu;
class RscButtonMenuOK;
class RscButtonMenuCancel;
class RscButtonMenuSteam;
class RscMapControl;
class RscMapControlEmpty;
class RscCheckBox;</syntaxhighlight>

=== RscDisplayName.hpp ===
<syntaxhighlight lang="cpp">class RscDisplayName
{
	idd = 1234;
	class ControlsBackground
	{
		class Background : RscText
		{
			idc = -1;
			x = GUI_GRID_CENTER_X;
			y = GUI_GRID_CENTER_Y;
			w = 40 * GUI_GRID_CENTER_W;
			h = 25 * GUI_GRID_CENTER_H;
			colorBackground[] = {0,0,0,0.8};
		};
	};
	class Controls
	{
		class ClickMe : RscButton
		{
			idc = -1;
			text = "Click Me!";
			onButtonClick = "hint 'You clicked the button!';";
			x = GUI_GRID_CENTER_X + 10 * GUI_GRID_CENTER_W;
			y = GUI_GRID_CENTER_Y + 12 * GUI_GRID_CENTER_H;
			w = 20 * GUI_GRID_CENTER_W;
			h = 1 * GUI_GRID_CENTER_H;
		};
	};
};
</syntaxhighlight>

=== RscMyHUD.hpp ===
<syntaxhighlight lang="cpp">class RscMyHUD
{
	idd = -1;
	onLoad = "uiNamespace setVariable ['RscMyHUD', _this select 0];";
	duration = 10;
	fadeIn = 1;
	fadeOut = 1;
	class Controls
	{
		class CenterText : RscStructuredText
		{
			text = "This text box will stay here for 10 seconds. You can still move and look around.";
			x = GUI_GRID_CENTER_X;
			y = GUI_GRID_CENTER_Y;
			w = 40 * GUI_GRID_CENTER_W;
			h = 25 * GUI_GRID_CENTER_H;
			colorBackground[] = {0,0,0,0.8};
		};
	};
};
</syntaxhighlight>

=== Creating the UIs ingame ===

For the dialog execute:
<sqf>createDialog "RscDisplayName";</sqf>
And for the HUD:
<sqf>("RscMyHUD_layer" call BIS_fnc_rscLayer) cutRsc ["RscMyHUD", "PLAIN"];</sqf>
Note: The {{hl|BIS_fnc_rscLayer}} call is not really necessary, as well as having a named layer at all, but this is the recommended way.


== Summary ==

* A UI consists of the following parts:
** Base controls to inherit from
** The display
** UIEHs
* You can get the base controls in a few different ways
* The display contains a list of (non) interactable controls
* These controls can have different styles and functionalities
* You can use the GUI Editor or external tools to have a "What You See Is What You Get" approach
* UIEHs can detect interactions with the UI


== Afterword ==

Now it is up to you to create some UIs. If you have questions feel free to ask them on the BI Forums for {{Link|link= https://forums.bohemia.net/forums/forum/154-arma-3-mission-editing-scripting/|text= mission makers}} or {{Link|link= https://forums.bohemia.net/forums/forum/162-arma-3-addons-configs-scripting/|text= addon makers}}. You can also find a Discord channel dedicated to GUI editing on the {{Link|https://discord.com/invite/arma|Arma 3 Discord}}.


= Advanced UI Creation =

This part will list some of the more advanced techniques to create and handle UIs. The list is somewhat unordered, as it is more of a list of "nice to know" things.


== Faster Debugging ==

=== Mission ===

The mission config is reloaded every time the mission is saved or when you return from the preview to [[:Category:Eden Editor|Eden]]. Instead of previewing the mission and creating your UI it is possible to instead preview the UI in Eden directly. Execute the following command in the Debug Console while in Eden:
<sqf>findDisplay 313 createDisplay "RscDisplayAAR";</sqf>
Your UI is created on top of the [[Arma 3: IDD List|Eden display (IDD: 313)]]. Now you can simply make changes to the UI, close the display, save the mission and execute the command again. The changes should now take effect.
{{Feature|informative|Be aware that interacting with mission objects is not possible (or at least different) while in Eden! This debugging method is meant to be used for changes to the design.}}

=== Addon ===

{{Feature|important|You need to run the [[Arma 3: Diagnostics Exe]] to use the [[diag_mergeConfigFile]] command!}}
The [[diag_mergeConfigFile]] command will enable you to reload the UI's config without having to restart the game or repack the mod. Here is a little script that would do just that:
<sqf>
diag_mergeConfigFile ["P:\MyModFolder\config.cpp"];
([findDisplay 49, findDisplay 313] select is3DEN) createDisplay "RscDisplayAAR";
</sqf>
The second line either creates your dialog on top of the Eden display, if you are in Eden, or on top of the escape menu when you are ingame.


== [[BIS_fnc_initDisplay]] ==

{{Feature|informative|Only available for addons!}}
When creating a mod you are able to utilize [[BIS_fnc_initDisplay]] which will handle parts of your UI. As an example we will be taking a look at an Arma 3 display called {{hl|RscDisplayAAR}}.

=== Compiling display script to uiNamespace ===

The partial config of {{hl|RscDisplayAAR}} looks like this:
<syntaxhighlight lang="cpp">
class RscDisplayAAR
{
	scriptName = "RscDisplayAAR";
	scriptPath = "GUI";
	onLoad = "[""onLoad"",_this,""RscDisplayAAR"",'GUI'] call 	(uinamespace getvariable 'BIS_fnc_initDisplay')";
	onUnload = "[""onUnload"",_this,""RscDisplayAAR"",'GUI'] call 	(uinamespace getvariable 'BIS_fnc_initDisplay')";
	idd = 2121;
	//...</syntaxhighlight>

We can utilize the {{hl|INIT_DISPLAY}} macro from "\a3\ui_f\hpp\defineCommon.inc" to shorten that config:
<syntaxhighlight lang="cpp">#include "\a3\ui_f\hpp\defineCommon.inc"
class RscDisplayAAR
{
	INIT_DISPLAY(RscDisplayAAR,GUI)
	idd = 2121;
	//...</syntaxhighlight>

Now let's see what these attributes do. On game start [[BIS_fnc_initDisplay]] will look through the following configs to search for UIs:
* <sqf>configFile</sqf>
* <sqf>configFile >> "RscTitles"</sqf>
* <sqf>configFile >> "RscIngameUI"</sqf>
* <sqf>configFile >> "Cfg3den" >> "Attributes"</sqf>
If a class has the attributes {{hl|scriptName}} and {{hl|scriptPath}} (and the attribute {{hl|scriptIsInternal}} is not defined or 0) then the display function is compiled into uiNamespace in the following way:
* {{hl|scriptPath}} points to a config attribute in <sqf inline>configFile >> "CfgScriptPaths"</sqf>
* The value of that attribute points to a folder which contains the sqf file with the name provided by {{hl|scriptName}}
* This script is compiled to uiNamespace as the value given by the {{hl|scriptName}} attribute and appended by "_script"
In case of {{hl|RscDisplayAAR}}:
* {{hl|scriptPath}} is "GUI"
* The value of the attribute "GUI" from <sqf inline>configFile >> "CfgScriptPaths"</sqf> is "A3\ui_f\scripts\GUI\"
* The script "A3\ui_f\scripts\GUI\RscDisplayAAR.sqf" is compiled as {{hl|RscDisplayAAR_script}} to [[uiNamespace]]

=== Handling onLoad and onUnload UIEHs ===

[[BIS_fnc_initDisplay]] is meant to be called from the onLoad and onUnload UIEH of the display as you can see in the config above. In both UIEHs the display's function is called with the following parameters:
<sqf>params ["_mode", "_params", "_class"];</sqf>
* _mode: [[String]] - either "onLoad" or "onUnload"
* _params: [[Array]] - The parameters of the [[User_Interface_Event_Handlers#onLoad|onLoad]] or [[User_Interface_Event_Handlers#onUnload|onUnload]] UIEH
* _class: [[String]] - The classname of the display

Here is an overview of the variables that are introduced by BIS_fnc_initDisplay. All variables are updated in the onLoad and onUnload UIEH.
{| class="wikitable"
|-
! Variable !! Namespace !! Explanation !! Example
|-
| RscDisplayName_script || [[uiNamespace]] || The display's script as defined by the {{hl|scriptPath}} and {{hl|scriptName}} attributes || <sqf>_script = uiNamespace getVariable "RscDisplayAAR_script"</sqf>
|-
| RscDisplayName || [[uiNamespace]] || Reference to the display which can be used with [[:Category:Command_Group:_GUI_Control|GUI commands]] || <sqf>_display = uiNamespace getVariable "RscDisplayAAR"</sqf>
|-
| BIS_fnc_initDisplay_configClass || Display || Config path of the display || <sqf>_configName = _display getVariable "BIS_fnc_initDisplay_configClass"</sqf>
|-
| PREFIX_displays || [[uiNamespace]] || List of open displays with the PREFIX provided as the fourth param of the function || <sqf>_displays = uiNamespace getVariable "GUI_displays";</sqf>
|}

==== Scripted Event Handlers ====
The function calls the following [[Arma_3:_Scripted_Event_Handlers|Scripted Eventhandlers]]:
* {{hl|OnDisplayRegistered}}
* {{hl|OnDisplayUnregistered}}
In both cases the scripted eventhandlers are executed in [[missionNamespace]] and the display and the classname of the display are passed as arguments.
<sqf>params ["_display", "_class"];</sqf>

Example:
<sqf>
[] spawn {
	[missionNamespace, "OnDisplayRegistered", {
		params ["_display", "_class"];
		if (_class == "RscDisplayFunctionsViewer") then {
			systemChat "You opened the Functions Viewer!";
		};
	}] call BIS_fnc_addScriptedEventHandler;

	[missionNamespace, "OnDisplayUnregistered", {
		params ["_display", "_class"];
		if (_class == "RscDisplayFunctionsViewer") then {
			systemChat "You closed the Functions Viewer!";
		};
	}] call BIS_fnc_addScriptedEventHandler;

	// Execute in Eden:
	_display = findDisplay 313 createDisplay "RscDisplayFunctionsViewer"; // -> You opened the Functions Viewer!
	uiSleep 2;
	_display closeDisplay 1; // -> You closed the Functions Viewer!
};
</sqf>

== UI Scripts ==

This section will explain how BI handles the sqf part of their dialogs. Most, if not all, UIs rely on BIS_fnc_initDisplay. As explained earlier, this function compiles and calls the script for the display. Most of the UI scripts can be found in the game files under {{hl|\a3\ui_f\scripts}}. A very basic UI script might look like this:
<sqf>
#define SELF RscDisplayTest_script
#include "path\to\idcMacros.inc"
params ["_mode", "_params", "_class"];
switch _mode do
{
	case "onLoad":
	{
		_params params ["_display"];
		_ctrlText = _display displayCtrl IDC_RSCDISPLAYTEST_TEXT;
		_ctrlText ctrlSetText str time;
		_ctrlHint = _display displayCtrl IDC_RSCDISPLAYTEST_HINT;
		_ctrlHint ctrlAddEventHandler ["ButtonClick", {
			with uiNamespace do {["ShowHint", _this] call SELF;};
		}];
	};
	case "ShowHint":
	{
		_params params ["_ctrlHint"];
		_ctrlHint ctrlSetBackgroundColor [1,0,0,1];
		hint "Changed background color to red";
	};
	case "onUnload":
	{
		_params params ["_display", "_exitCode"];
	};
};
</sqf>
<sqf inline>#define SELF RscDisplayTest_script</sqf> - The macro "SELF" refers to the UI's script in the uiNamespace set by [[BIS_fnc_initDisplay]].

<sqf inline>#include "path\to\idcMacros.inc"</sqf> - This line will move the content of the given file to this script. In our case that file might look like this:
<syntaxhighlight lang="cpp">
//--- RscDisplayTest
#define IDD_RSCDISPLAYTEST 1234
#define IDC_RSCDISPLAYTEST_TEXT 1000
#define IDC_RSCDISPLAYTEST_HINT 1001
</syntaxhighlight>
The idcs must match the config, the idcMacros.inc file is included in the description.ext/config.cpp:
<syntaxhighlight lang="cpp">
class RscDisplayTest
{
	idd = IDD_RSCDISPLAYTEST;
	...
	class Controls
	{
		class Text : RscStructuredText
		{
			idc = IDC_RSCDISPLAYTEST_TEXT;
			...
		};
		class Hint : RscButton
		{
			idc = IDC_RSCDISPLAYTEST_HINT;
			...
		};
	};
};</syntaxhighlight>

Now we can use the macros instead of the idcs. This makes changing the idc of a given control way easier as you only have to change one line instead of tracking down every instance where you used the idc. The extension ".inc" usually denotes a file that can be included by configs and sqf scripts alike.

<sqf inline>params ["_mode", "_params", "_class"];</sqf> - Since the script is called from [[BIS_fnc_initDisplay]] it will contain these params. We will also use the same structure for any subsequent calls of our script as we will see later.

<sqf inline>switch _mode do</sqf> - Using a [[switch]] will enable us to reuse the same script for different purposes which are all related to the same UI.

<sqf inline>case "onLoad" // or "onUnload"</sqf> - These events are called by [[BIS_fnc_initDisplay]]. While both can be omitted, the [[User_Interface_Event_Handlers#onLoad|onLoad UIEH]] is used to set up the UI.

<sqf inline>_params params ["_display"];</sqf> - _params is an array which contains the arguments specific to the given case. In the case of the onLoad event it contains the arguments passed through [[BIS_fnc_initDisplay]] which are the same arguments used in the onLoad UIEH. The same applies to the [[User_Interface_Event_Handlers#onUnload|onUnload UIEH]] which passes a reference to the display as well as the exit code (number, 0 = OK, 2 = CANCEL).

<sqf inline>_ctrlText ctrlSetText str time;</sqf> - The [[User_Interface_Event_Handlers#onLoad|onLoad]] event is used to set the initial state of the display and...

<sqf inline>_ctrlHint ctrlAddEventHandler ["ButtonClick", { /* ... */ }];</sqf> - ...to add [[User_Interface_Event_Handlers|UIEHs]] to the controls.

<sqf inline>with uiNamespace do { ["ShowHint", _this] call SELF; };</sqf> - Since [[BIS_fnc_initDisplay]] compiles the script to [[uiNamespace]], we have to [[call]] it there too. This [[User_Interface_Event_Handlers|UIEH]] executes the "ShowHint" case of the script and passes the [[User_Interface_Event_Handlers|UIEH]]'s parameters directly to the script. The code of the [[User_Interface_Event_Handlers#onButtonClick|UIEH "ButtonClick"]] here knows nothing about the rest of the script. All local variables set beforehand are not available.

<sqf inline>case "ShowHint":</sqf> - You can add your own events to the script like this. Be aware that the [[switch]] is case sensitive!

<sqf inline>_params params ["_ctrlHint"];</sqf> - The [[User_Interface_Event_Handlers#onButtonClick|ButtonClick UIEH]] passes a reference to the clicked button inside the [[Magic_Variables#this|_this]] variable of the [[User_Interface_Event_Handlers|UIEH]] (or the _params variable in the script).


You can also take a look at {{hl|\a3\ui_f\scripts\GUI\RscDisplayInterruptEditorPreview.sqf}} for a short and simple example from the game. Keep in mind that the [[params]] command was probably not available at the time the script was written so [[private]] and [[select]] were used instead.


[[Category:Arma: Tutorials]] [[Category:GUI_Topics]]